[1] Wakayama Med Univ, Dept Surg 2, Wakayama 6418510, Japan
[2] Shizuoka Canc Ctr Hosp, Div Hepatobiliary Pancreat Surg, Shizuoka, Japan
[3] Nagoya Univ, Grad Sch Med, Dept Surg Gastroenterol, Nagoya, Aichi 4648601, Japan
[4] Osaka Univ, Grad Sch Med, Dept Surg, Osaka, Japan
[5] Hiroshima Univ, Grad Sch Biomed Sci, Dept Surg, Div Clin Med Sci, Hiroshima, Japan
[6] Yokohama City Univ, Med Ctr, Dept Biostat & Epidemiol, Yokohama, Kanagawa, Japan
[7] Nagoya Univ, Grad Sch Med, Program Hlth & Community Med, Nagoya, Aichi 4648601, Japan